1. Field of the Invention
The present invention mainly relates to a configuration of a relay server that enables communication between terminals.
2. Description of the Related Art
A communication technique referred to as VPN (Virtual Private Network) is known (see, e.g., Japanese Laid-Open Patent Publication No. 2002-217938). The VPN is utilized to communicate between terminals connected to a LAN (Local Area Network) of a plurality of branch offices (base points) provided in each of the regions over the Internet. Through the use of the VPN, another LAN in a remote location can be used as if it is a directly connected network.
However, this type of system tends to be rigid in terms of virtually building the network, and it is not easy to build a system having expandability and flexibility. The communication system disclosed in Japanese Laid-Open Patent Publication No. 2002-217938 cannot be used to arbitrarily set, for every base point, a terminal that can actually exchange data at a terminal that cannot exchange data between the base points at either base point.